:: ERROR ::Cross-thread operation not valid: Control 'TB_an1' accessed from a thread other than the thread it was created on. While trying to read .txt file to textBox.Text

Question

ERROR APPEARS ON THIS LINE:::::
StreamReader streamreader1an1 = new StreamReader(@tempPath + "an1.txt"); TB_an1.Text = streamreader1an1.ReadToEnd(); streamreader1an1.Close();

Error is: Cross-thread operation not valid: Control 'TB_an1' accessed from a thread other than the thread it was created on.

I don't understand the error :'(

The program below is the program...

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

using System.Runtime.InteropServices;
using System.Threading;
using System.Timers;
using System.Net;
using System.IO;

namespace Ultra_Tournment
{
public partial class Form1 : Form
{

private static System.Timers.Timer aTimer;
private static System.Timers.Timer bTimer;

public Form1()
{
InitializeComponent();
string tempPath = System.IO.Path.GetTempPath();
//

bTimer = new System.Timers.Timer(10000);

// Hook up the Elapsed event for the timer.
bTimer.Elapsed += new ElapsedEventHandler(OnTimedEventZ);

// Set the Interval to 2 seconds (2000 milliseconds).
bTimer.Interval = 6000;
bTimer.Enabled = true;

aTimer = new System.Timers.Timer(10000);

// Hook up the Elapsed event for the timer.
aTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent);

// Set the Interval to 2 seconds (2000 milliseconds).
aTimer.Interval = 5000;
aTimer.Enabled = true;

}

const int HT_CAPTION = 0x2;
const int WM_NCLBUTTONDOWN = 0xA1;

[DllImportAttribute("user32.dll")]
public static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam);
[DllImportAttribute("user32.dll")]
public static extern bool ReleaseCapture();

private void OnTimedEvent(object source, ElapsedEventArgs e)
{
string tempPath = System.IO.Path.GetTempPath();
//aNAME 1- 10
WebClient Client = new WebClient();
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/an1.txt", @tempPath+"an1.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/an2.txt", @tempPath + "an2.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/an3.txt", @tempPath + "an3.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/an4.txt", @tempPath + "an4.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/an5.txt", @tempPath + "an5.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/an6.txt", @tempPath + "an6.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/an7.txt", @tempPath + "an7.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/an8.txt", @tempPath + "an8.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/an9.txt", @tempPath + "an9.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/an10.txt", @tempPath + "an10.txt");

//bNAME 1-10
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bn1.txt", @tempPath + "bn1.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bn2.txt", @tempPath + "bn2.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bn3.txt", @tempPath + "bn3.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bn4.txt", @tempPath + "bn4.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bn5.txt", @tempPath + "bn5.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bn6.txt", @tempPath + "bn6.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bn7.txt", @tempPath + "bn7.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bn8.txt", @tempPath + "bn8.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bn9.txt", @tempPath + "bn9.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bn10.txt", @tempPath + "bn10.txt");

//bqty 1- 10

Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq1.txt", @tempPath + "aq1.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq2.txt", @tempPath + "aq2.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq3.txt", @tempPath + "aq3.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq4.txt", @tempPath + "aq4.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq5.txt", @tempPath + "aq5.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq6.txt", @tempPath + "aq6.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq7.txt", @tempPath + "aq7.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq8.txt", @tempPath + "aq8.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq9.txt", @tempPath + "aq9.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq10.txt", @tempPath + "aq10.txt");

//bqty 1-10

Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq1.txt", @tempPath + "bq1.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq2.txt", @tempPath + "bq2.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq3.txt", @tempPath + "bq3.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq4.txt", @tempPath + "bq4.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq5.txt", @tempPath + "bq5.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq6.txt", @tempPath + "bq6.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq7.txt", @tempPath + "bq7.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq8.txt", @tempPath + "bq8.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq9.txt", @tempPath + "bq9.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq10.txt", @tempPath + "bn10.txt");

//bqty 1- 10

Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq1.txt", @tempPath + "aq1.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq2.txt", @tempPath + "aq2.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq3.txt", @tempPath + "aq3.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq4.txt", @tempPath + "aq4.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq5.txt", @tempPath + "aq5.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq6.txt", @tempPath + "aq6.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq7.txt", @tempPath + "aq7.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq8.txt", @tempPath + "aq8.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq9.txt", @tempPath + "aq9.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq10.txt", @tempPath + "aq10.txt");

//bqty 1-10
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq1.txt", @tempPath + "bq1.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq2.txt", @tempPath + "bq2.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq3.txt", @tempPath + "bq3.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq4.txt", @tempPath + "bq4.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq5.txt", @tempPath + "bq5.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq6.txt", @tempPath + "bq6.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq7.txt", @tempPath + "bq7.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq8.txt", @tempPath + "bq8.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq9.txt", @tempPath + "bq9.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/bq10.txt", @tempPath + "bq10.txt");

//bqty 1- 10

Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq1.txt", @tempPath + "alr1.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq2.txt", @tempPath + "alr2.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq3.txt", @tempPath + "alr3.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq4.txt", @tempPath + "alr4.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq5.txt", @tempPath + "alr5.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq6.txt", @tempPath + "alr6.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq7.txt", @tempPath + "alr7.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq8.txt", @tempPath + "alr8.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq9.txt", @tempPath + "alr9.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq10.txt", @tempPath + "alr10.txt");

//bqty 1-10
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq1.txt", @tempPath + "blr1.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq2.txt", @tempPath + "blr2.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq3.txt", @tempPath + "blr3.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq4.txt", @tempPath + "blr4.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq5.txt", @tempPath + "blr5.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq6.txt", @tempPath + "blr6.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq7.txt", @tempPath + "blr7.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq8.txt", @tempPath + "blr8.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq9.txt", @tempPath + "blr9.txt");
Client.DownloadFile("http://ultracomputers.info/dakkon/aposta/aq10.txt", @tempPath + "blr10.txt");
Client.Dispose();

}
public void OnTimedEventZ(object source, ElapsedEventArgs e)
{
string tempPath = System.IO.Path.GetTempPath();
//an's

StreamReader streamreader1an1 = new StreamReader(@tempPath + "an1.txt"); TB_an1.Text = streamreader1an1.ReadToEnd(); streamreader1an1.Close();
StreamReader streamreader2an1 = new StreamReader(@tempPath + "an2.txt"); TB_an2.Text = streamreader2an1.ReadToEnd(); streamreader2an1.Close();
StreamReader streamreader3an1 = new StreamReader(@tempPath + "an3.txt"); TB_an3.Text = streamreader3an1.ReadToEnd(); streamreader3an1.Close();
StreamReader streamreader4an1 = new StreamReader(@tempPath + "an4.txt"); TB_an4.Text = streamreader4an1.ReadToEnd(); streamreader4an1.Close();
StreamReader streamreader5an1 = new StreamReader(@tempPath + "an5.txt"); TB_an5.Text = streamreader5an1.ReadToEnd(); streamreader5an1.Close();
StreamReader streamreader6an1 = new StreamReader(@tempPath + "an6.txt"); TB_an6.Text = streamreader6an1.ReadToEnd(); streamreader6an1.Close();
StreamReader streamreader7an1 = new StreamReader(@tempPath + "an7.txt"); TB_an7.Text = streamreader7an1.ReadToEnd(); streamreader7an1.Close();
StreamReader streamreader8an1 = new StreamReader(@tempPath + "an8.txt"); TB_an8.Text = streamreader8an1.ReadToEnd(); streamreader8an1.Close();
StreamReader streamreader9an1 = new StreamReader(@tempPath + "an9.txt"); TB_an9.Text = streamreader9an1.ReadToEnd(); streamreader9an1.Close();
StreamReader streamreader10an1 = new StreamReader(@tempPath + "an10.txt"); TB_an10.Text = streamreader10an1.ReadToEnd(); streamreader10an1.Close();

//bn's
StreamReader streamreader1bn1 = new StreamReader(@tempPath + "bn1.txt"); TB_bn1.Text = streamreader1bn1.ReadToEnd(); streamreader1bn1.Close();
StreamReader streamreader2bn1 = new StreamReader(@tempPath + "bn2.txt"); TB_bn2.Text = streamreader2bn1.ReadToEnd(); streamreader2bn1.Close();
StreamReader streamreader3bn1 = new StreamReader(@tempPath + "bn3.txt"); TB_bn3.Text = streamreader3bn1.ReadToEnd(); streamreader3bn1.Close();
StreamReader streamreader4bn1 = new StreamReader(@tempPath + "bn4.txt"); TB_bn4.Text = streamreader4bn1.ReadToEnd(); streamreader4bn1.Close();
StreamReader streamreader5bn1 = new StreamReader(@tempPath + "bn5.txt"); TB_bn5.Text = streamreader5bn1.ReadToEnd(); streamreader5bn1.Close();
StreamReader streamreader6bn1 = new StreamReader(@tempPath + "bn6.txt"); TB_bn6.Text = streamreader6bn1.ReadToEnd(); streamreader6bn1.Close();
StreamReader streamreader7bn1 = new StreamReader(@tempPath + "bn7.txt"); TB_bn7.Text = streamreader7bn1.ReadToEnd(); streamreader7bn1.Close();
StreamReader streamreader8bn1 = new StreamReader(@tempPath + "bn8.txt"); TB_bn8.Text = streamreader8bn1.ReadToEnd(); streamreader8bn1.Close();
StreamReader streamreader9bn1 = new StreamReader(@tempPath + "bn9.txt"); TB_bn9.Text = streamreader9bn1.ReadToEnd(); streamreader9bn1.Close();
StreamReader streamreader10bn1 = new StreamReader(@tempPath + "bn10.txt"); TB_bn10.Text = streamreader10bn1.ReadToEnd(); streamreader10bn1.Close();

//aqts
StreamReader streamreader1aq1 = new StreamReader(@tempPath + "aq1.txt"); TB_aq1.Text = streamreader1aq1.ReadToEnd(); streamreader1aq1.Close();
StreamReader streamreader2aq1 = new StreamReader(@tempPath + "aq2.txt"); TB_aq2.Text = streamreader2aq1.ReadToEnd(); streamreader2aq1.Close();
StreamReader streamreader3aq1 = new StreamReader(@tempPath + "aq3.txt"); TB_aq3.Text = streamreader3aq1.ReadToEnd(); streamreader3aq1.Close();
StreamReader streamreader4aq1 = new StreamReader(@tempPath + "aq4.txt"); TB_aq4.Text = streamreader4aq1.ReadToEnd(); streamreader4aq1.Close();
StreamReader streamreader5aq1 = new StreamReader(@tempPath + "aq5.txt"); TB_aq5.Text = streamreader5aq1.ReadToEnd(); streamreader5aq1.Close();
StreamReader streamreader6aq1 = new StreamReader(@tempPath + "aq6.txt"); TB_aq6.Text = streamreader6aq1.ReadToEnd(); streamreader6aq1.Close();
StreamReader streamreader7aq1 = new StreamReader(@tempPath + "aq7.txt"); TB_aq7.Text = streamreader7aq1.ReadToEnd(); streamreader7aq1.Close();
StreamReader streamreader8aq1 = new StreamReader(@tempPath + "aq8.txt"); TB_aq8.Text = streamreader8aq1.ReadToEnd(); streamreader8aq1.Close();
StreamReader streamreader9aq1 = new StreamReader(@tempPath + "aq9.txt"); TB_aq9.Text = streamreader9aq1.ReadToEnd(); streamreader9aq1.Close();
StreamReader streamreader10aq1 = new StreamReader(@tempPath + "aq10.txt"); TB_aq10.Text = streamreader10aq1.ReadToEnd(); streamreader10aq1.Close();

//bqts
StreamReader streamreader1bq1 = new StreamReader(@tempPath + "bq1.txt"); TB_bq1.Text = streamreader1bq1.ReadToEnd(); streamreader1bq1.Close();
StreamReader streamreader2bq1 = new StreamReader(@tempPath + "bq2.txt"); TB_bq2.Text = streamreader2bq1.ReadToEnd(); streamreader2bq1.Close();
StreamReader streamreader3bq1 = new StreamReader(@tempPath + "bq3.txt"); TB_bq3.Text = streamreader3bq1.ReadToEnd(); streamreader3bq1.Close();
StreamReader streamreader4bq1 = new StreamReader(@tempPath + "bq4.txt"); TB_bq4.Text = streamreader4bq1.ReadToEnd(); streamreader4bq1.Close();
StreamReader streamreader5bq1 = new StreamReader(@tempPath + "bq5.txt"); TB_bq5.Text = streamreader5bq1.ReadToEnd(); streamreader5bq1.Close();
StreamReader streamreader6bq1 = new StreamReader(@tempPath + "bq6.txt"); TB_bq6.Text = streamreader6bq1.ReadToEnd(); streamreader6bq1.Close();
StreamReader streamreader7bq1 = new StreamReader(@tempPath + "bq7.txt"); TB_bq7.Text = streamreader7bq1.ReadToEnd(); streamreader7bq1.Close();
StreamReader streamreader8bq1 = new StreamReader(@tempPath + "bq8.txt"); TB_bq8.Text = streamreader8bq1.ReadToEnd(); streamreader8bq1.Close();
StreamReader streamreader9bq1 = new StreamReader(@tempPath + "bq9.txt"); TB_bq9.Text = streamreader9bq1.ReadToEnd(); streamreader9bq1.Close();
StreamReader streamreader10bq1 = new StreamReader(@tempPath + "bq10.txt"); TB_bq10.Text = streamreader10bq1.ReadToEnd(); streamreader10bq1.Close();

//arl
StreamReader streamreader1alr1 = new StreamReader(@tempPath + "alr1.txt"); TB_alr1.Text = streamreader1alr1.ReadToEnd(); streamreader1alr1.Close();
StreamReader streamreader2alr1 = new StreamReader(@tempPath + "alr2.txt"); TB_alr2.Text = streamreader2alr1.ReadToEnd(); streamreader2alr1.Close();
StreamReader streamreader3alr1 = new StreamReader(@tempPath + "alr3.txt"); TB_alr3.Text = streamreader3alr1.ReadToEnd(); streamreader3alr1.Close();
StreamReader streamreader4alr1 = new StreamReader(@tempPath + "alr4.txt"); TB_alr4.Text = streamreader4alr1.ReadToEnd(); streamreader4alr1.Close();
StreamReader streamreader5alr1 = new StreamReader(@tempPath + "alr5.txt"); TB_alr5.Text = streamreader5alr1.ReadToEnd(); streamreader5alr1.Close();
StreamReader streamreader6alr1 = new StreamReader(@tempPath + "alr6.txt"); TB_alr6.Text = streamreader6alr1.ReadToEnd(); streamreader6alr1.Close();
StreamReader streamreader7alr1 = new StreamReader(@tempPath + "alr7.txt"); TB_alr7.Text = streamreader7alr1.ReadToEnd(); streamreader7alr1.Close();
StreamReader streamreader8alr1 = new StreamReader(@tempPath + "alr8.txt"); TB_alr8.Text = streamreader8alr1.ReadToEnd(); streamreader8alr1.Close();
StreamReader streamreader9alr1 = new StreamReader(@tempPath + "alr9.txt"); TB_alr9.Text = streamreader9alr1.ReadToEnd(); streamreader9alr1.Close();
StreamReader streamreader10alr1 = new StreamReader(@tempPath + "alr10.txt"); TB_alr10.Text = streamreader10alr1.ReadToEnd(); streamreader10alr1.Close();

//brl

StreamReader streamreader1blr1 = new StreamReader(@tempPath + "blr1.txt"); TB_blr1.Text = streamreader1blr1.ReadToEnd(); streamreader1blr1.Close();
StreamReader streamreader2blr1 = new StreamReader(@tempPath + "blr2.txt"); TB_blr2.Text = streamreader2blr1.ReadToEnd(); streamreader2blr1.Close();
StreamReader streamreader3blr1 = new StreamReader(@tempPath + "blr3.txt"); TB_blr3.Text = streamreader3blr1.ReadToEnd(); streamreader3blr1.Close();
StreamReader streamreader4blr1 = new StreamReader(@tempPath + "blr4.txt"); TB_blr4.Text = streamreader4blr1.ReadToEnd(); streamreader4blr1.Close();
StreamReader streamreader5blr1 = new StreamReader(@tempPath + "blr5.txt"); TB_blr5.Text = streamreader5blr1.ReadToEnd(); streamreader5blr1.Close();
StreamReader streamreader6blr1 = new StreamReader(@tempPath + "blr6.txt"); TB_blr6.Text = streamreader6blr1.ReadToEnd(); streamreader6blr1.Close();
StreamReader streamreader7blr1 = new StreamReader(@tempPath + "blr7.txt"); TB_blr7.Text = streamreader7blr1.ReadToEnd(); streamreader7blr1.Close();
StreamReader streamreader8blr1 = new StreamReader(@tempPath + "blr8.txt"); TB_blr8.Text = streamreader8blr1.ReadToEnd(); streamreader8blr1.Close();
StreamReader streamreader9blr1 = new StreamReader(@tempPath + "blr9.txt"); TB_blr9.Text = streamreader9blr1.ReadToEnd(); streamreader9blr1.Close();
StreamReader streamreader10blr1 = new StreamReader(@tempPath + "blr10.txt"); TB_blr10.Text = streamreader10blr1.ReadToEnd(); streamreader10blr1.Close();

}

private void Form1_Load(object sender, EventArgs e)
{

}

private void TB_an1_TextChanged(object sender, EventArgs e)
{

}

private void TB_blr10_TextChanged(object sender, EventArgs e)
{

}

}
}

I posted the line that has the errors, in the beggining...

I dont understand... I want to be able to read line to textbox, after it downloaded it, did I do something wrong ?

Vulpes · Answer

See if the error goes away if you replace this line: TB_an1.Text = streamreader1an1.ReadToEnd(); with this: this.Invoke(new MethodInvoker(delegate() { TB_an1.Text = streamreader1an1.ReadToEnd(); })); If it doesn't go away then try replacing Invoke with BeginInvoke. What we're doing here is marshalling the updating of the textbox to the UI thread where it was created.

Sam Hobbs · Answer

I have begun learning Android programming and for what it is worth Android has a similar design; with it it is also not possible to access the UI from a different thread.

Vulpes · Answer

Although it may look fancy it isn't really :) Windows Forms has a rule that you should only access controls such as a textbox from the thread on which they were created which is normally the application's main 'user interface' thread. If you're using a multi-threaded timer then you will get a 'cross-thread operation not valid error' if you try to update a control's state from a thread which the timer is using. To avoid this error Windows Forms provides two ways to marshal such a call back to the UI thread. These are the Invoke method (for synchronous operations) and the BeginInvoke method (for asynchronous operations). Both of these methods take a delegate as a parameter which contains the method to be called to perform the operations on the UI thread. Now the .NET framework contains a built in delegate class called MethodInvoker which can execute any method that is declared void and takes no parameters. This is ideal here. Also rather than declare a separate 'named' method containing just one line we can declare an 'anonymous method' containing this line and execute that instead. The anonymous method is this part of the code: delegate() { TB_an1.Text = streamreader1an1.ReadToEnd(); } So I think you'll be able to see now where all the closing brackets come from :) Incidentally from .NET 3.5 onwards you can use a lambda expression rather than an anonymous method but as I wasn't sure whether you were using this I've stuck to the 'old' way. If you're not sure whether Invoke is needed or not you can always check it using the Control.InvokeRequired property and then provide Invoke code if the property is true or 'normal' code otherwise.

thiago costa · Answer

HAHAHAHAHAHAHAHAHAHAHHA !!!!!!!!!!!!!!!!!!!!!!!!!!!!!! this.Invoke(new MethodInvoker(delegate(){TB_an1.Text = streamreader1an1.ReadToEnd();})); WORKED 100%% !!!! I don't understand what I did wrong to begin with... I have no clue what just happened... lol im so confused.. IT WORKED !!!! but I don't understand how... Also that line is wicked confusing It has like ;})); Hey Thank you so much ... SO SO SO SO much :D THANKS !!!